Stick to Two or Three Types for Consistency In the Pokmon games having a team with lots of different types is great, but in the Trading Card Game
Pokmon TCG Pocket nails the trifecta: accessibility, aesthetic appeal, and nostalgic hooks, all wrapped in a truly mobile-first, polished experience
By using multi-color cards as leader cards, you can build a multi-color deck
Instead of just being multicolored themselves, they care about other multicolor interactions
Plus, they can still be put into their owners graveyard if their toughness becomes 0/0 via anything that would give minus counters (-X/-X), such as the infect ability
Shiny Rares mark the debut of shinies in Pokmon TCG Pocket and are quite rare, to say the least